This is the list of changes since the previous release, 3.3.3
Added features
Explanatory text regarding archive restoration in the Core release, when you visit the Administer Backup Files page
Improved message in the case of an error which will help you solve the issue yourself
ACL checks in the backup status administrator module
Row-level filtering is now possible (by creating a PHP filter file)
ABI is now self-documenting; no excuses for not reading the fine manual any more!
Added warning about UNC paths when used as the site's root, since PHP is very often buggy with respect to UNC paths
Miscellaneous Changes
Modified the success message after taking a System Restore Point, backing up before upgrading Joomla! or otherwise take a backup as part of an automated process with a return URL
backup.php now returns exit code 1 if there were warnings or 2 if the backup failed on an error
Changed Akeeba Backup's installation page to better lead you to your next steps.
Renamed jquery.js to akeebajq.js due to some system plugins removing all instances of jquery.js from the page source (whichever idiot wrote them!)
Renamed jquery-ui.js to akeebajqui.js due to some system plugins removing all instances of jquery-ui.js from the page source (whichever idiot wrote them!)
Updated SRP definitions for Akeeba Backup, Admin Tools, Akeeba Subscriptions and Akeeba Release System
Bug fixes
tmp directory would not be cleaned up after extensions installation when SRP is used
The Configuration page would not render on IE7, IE8 and IE9 (the latter only when using Compatibility mode)
Backup age quotas caused the backup finalization to crash on PHP 5.2
--quiet option added to backup.phpto suppress output except warnings and errors
When using a developer's release, Live Update would always report that a newer version is available
When a Windows server is using a UNC path for the site's root, the backup always failed
When jQuery wasn't loaded, the message urged you to use Google AJAX API, which is no longer an option.
ABI: Would always report that the storage isn't working when the session save path is unwritable but ABI could create a storage file to store session information.
Quotas would delete the most recent files, not the oldest files